I did a pair of these vehicles in 2010. All the articulated joints in the legs presented a huge challenge. While it made them quite pose able, there was little or no strength in them... at least not enough to bear the massive weight of the bodies.
So, I put a flying base support under each of them, and took all the weight from the legs. That allowed me to make the fun movement trays for them!
And the trays for both miniatures: